Fuse construction



July l 1947- w. o. scHUL-rz 2,423,258

FUSE CONSTRUCTION Filed May 24, 1934 2 Sheets-Sheet 1 l\ 56 Z4( 6 z5 5 INVENTORI July 1, 1947.

W. O. SCH ULTZ FUSE CONSTRUCTION Filed May 24, 1934 2 Sheets-Sheet 2 ATTORNE Patented July l, 1947 FUSE CONSTRUCTION William 0. Schultz, South Milwaukee, Wis., assignor to Line Material Company, South Milwaukee, Wis., a corporation of Delaware Application May 24, 1934, Serial No. 727,250

48 Claims. l

This invention relates to fuse constructions and is particularly directed to a drop-out type of fuse.

Objects of this invent-ion are to provide a novel form of fuse. such as the expulsion fuse type, in which the fuse tube operates rst in the manner of an expulsion fuse, then moves downward- 1y and increases the gap in the circuit, and nally comes to rest projecting outwardly from the body portion so as to give a visual signal indicating that the fuse has blown.

In greater detail, objects oi this invention are to provide a housed type of expulsion fuse in which the fuse tube is biased towards motion axially of the fuse tube and downwardly and outwardly from the housing and is normally restrained from such motion by the fuse link, the rupturing of the fuse link releasing the fuse tube and allowing such outwardly biased fuse tube to be projected downwardly and outwardly from the housing.

Further objects are to provide a construction in which the lower fastening means for the` fuse link is so constructed that it tends to quickly withdraw whatever remains of the lower portion of the fuse link from the fuse tube, such action being also assisted by gas pressure generated within the fuse tube, so that the combination of these two features insures the extinguishing of the arc within the fuse tube in a much shorter time than with the usual type of expulsion fuse, the fuse tube itself sliding vertically downwardly and increasing the gap formed in the circuit.

Further objects are to provide a construction in which the downward motion of the fuse tube is facilitated, in which latching means are provided for normally holding the fuse tube in elevated position, and in which means are provided for positively releasing the latching means when the fuse link is ruptured thus insuring the release of the fuse tube.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a side elevation of one form of the device with parts in vertical section, such view showing in dotted lines the iinal position of the fuse tube after the fuse link has been ruptured.

Figure 2 is a sectional view on the line 22 of Figure l.

Figure 3 is a fragmentary detail view, such View corresponding to a section on the line 3 3 of Figure 1.

Figure 4 is a view corresponding to Figure l showing a modified form of the invention.

Referring to the drawings, particularly Figures 1, 2 and 3, it will be seen that the fuse comprises a housing I which may be of any suitable insulating material such as porcelain to which a door 2 is hingedly joined adjacent its lower end in any suitable manner, as by means of the transverse pin 3. 'I'he door may be of a phenolic condensation product or other suitable insulating material. It is provided with an eye or handle 4 for facilitating the opening of the door.

Any suitable means may be provided for holding the door closed when the fuse tube is removed. For example. a spring' clip 5 may be carried by the door and may fit within an indentation formed in the upper portion of the housing. The housing is preferably provided with a barrier -B intermediate its ends and with upper and lower terminal members 'I and 8. The lower terminal member 8 carries a. pair of outwardly projecting prongs or spring arms 9 which may y have outwardly turned ends and which clamp around or yieldingly bind against the lower contact I0 of the fuse tube II. The upper terminal member 'I may be provided with a spring arm I2 whose inturned end I3 engages the. upper contact I 4 of the expulsion fuse. If desired, an additional spring member I5 may be provided to bear against the inturned portion I3 and increasethe spring pressure and improve the electrical contact between the rounded upper end of the upper contact I 4 of the fuse tube and the member I3.

The door 2 is provided with a out out upper portion I 6 to accommodate the member-I2 and with a lower cut out portion I1 within which the hooked end I8 of the lower contact I0 is received. A pair of bosses I9 are formed integral with the door 2 and project inwardly within the cut out portion I1. These bosses carry a transverse strap or plate 20' behind which the hook I8 is positioned when the fuse tube is lockediin place. The bosses also carry a pair of V-shaped spring arms 2| which press downwardly against lugs 22 formed on the lower contact I0 of the fuse tube and thus hold the hook I8 locked'to the plate 20.

Preferably the hook I8 is provided with a lower bevelled face, as indicated, so that when the fuse tube is pressed towards the door to position it, the bevelled lower face of the hook I8 rides over the plate 20 and thus raises the fuse tube, compressing the springs 2| until the hook snaps into place. The springs yieldingly hold the contact I Il downwardly and the hook I8 in interlocking relation with the plate 20. The upper end of the door is provided with a rounded cut out portion 23 within which the upper contact I4 seats to thus more securely position the fuse tube. The upper and lower contacts are joined by the fuse link 24 in the usual manner, and it is preferable to provide a small notch 25 in the lower portion of the fuse tube through which the fuse link passes.

It is to be noted particularly that the lower contact l is not rigidly secured to the insulating body portion of the fuse tube, but in reality it constitutes a sleeve loosely and freely receiving the fuse tube so that the fuse tube may slide through this sleeve or lower contact I0. This sleeve thus forms in reality a cradle within which the fuse tube is slidably mounted.

The fuse tube is provided with a collar 26 rigidly secured at a position slightly above its lower end and which is provided with outwardly projecting rollers 21. These rollers are normally engaged by the hooklike arm 28 of a latch and contact member 29. This member 29 has a pair of upper ears 30 which are pivoted to ears 3| formed integrally with the cradle contact or sleeve I0, as shown most clearly in Figure 3.

A pintle pin 32 passes through the ears and a spring 33 is positioned around the pin and urges the latch member 29 in a clockwise direction, as viewed in Figure 1. However, this contact member 29 is prevented from moving outwardly by means of the fuse link which is clamped to the face of the contact member 29 by means of a thumb nut 34, see Figure 1. The lower swinging or pivoted contact 29 is thus restrained from movement by the fuse link itself. The lower contact, however, is biased towards motion in a clockwise direction, as stated, by means of the spring and as indicated by the arrow in Figure 1. Preferably a flexible conductingr leader 35 joins the pivoted contact member 29 and the lower contact l0.

The operation of the apparatus is as follows: When the fuse blows and the fuse link is ruptured, the lower pivoted contact member 29 is released and swings in a clockwise direction under the influence of the spring 33. This withdraws the hooklike arms 29 from the rollers 21 and thus releases the fuse tube II. The fuse tube H, after the reactive forces of the gases has ceased, drops downwardly into the dotted line position and projects beyond the lower portion of the housing through an opening 36 formed in the lower portion of the door.

It is to be noted that although an abutment or bearing surface 31 is formed on the door 2 against which the contact i0 bears. that neverltlieless the free sliding action of the fuse tube is not interfered with, as the fuse tube slides through the contact l0.

It is to be noted particularly that the fuse acts as an expulsion fuse and secures the clearing action common to expulsion fuses. However, it has the additional advantage of pulling whatever remains of the lower portion of the severed fuse link quickly from the fuse tube due to the motion of the member 29, thus clearing the fuse with the utmost speed.

Further than this, it is to be noted that this device provides a visual indication of the condition of the fuse for when the fuse has blown, the fuse tube projects downwardly below the housing and thus visually indicates the condition of the fuse.

In the form of the invention shown in Figure 4, the housing 38 is substantially similar to housing I with the exception of the construction oi the spring blade terminals for cooperation with the fuse tube and the opening in the bottom of the housing, The lower terminal member 45 carries a downwardly projecting pair of spring arms which are looped, as indicated at 61, and which terminate in lower arms 69. These lower arms are constantly yicldingly urged outwardly. They bear adjacent their lower ends against the cam like ears 10 of the rocking lower Contact member 1|. This contact member 1| is pivotally carried from the lower contact 12 of the fuse tube 13. The upper end of the fuse tube is provided with a conical or tapered portion 49 which is gripped between the spring arms 46 of the upper fuse box terminal, fastened to the back of the box to the upper terminal member corresponding to the member 1 of Figure l. This engagement of the upper end of the tube is such as not to interfere with the free downwardly sliding motion of the fuse tube. Also the upper end 49 is positioned loosely within an aperture 5| of a U-shaped clip 52 carried by the upper end of the door. This cllip is provided with a downwardly turned portion 53 which fits between the converging spring arms 46 and thus serves to releasably hold the upper end of the door closed even if the fuse tube is removed. The fuse tube 13 is held in a slightly different manner to the door from that previously described. The upper contact portion 14 and the lower contact portion 12 are provided with upwardly turned cam hook members 15 and 1G respectively which t behind the lower end of the clip 11 and of the transverse bar 18 carried by the door.

Further, a spring 19 is also carried by the door and hooks beneath the projecting ears formed on the lower Contact portion T2. The fuse is positioned by hooking the hooks behind their respective members and moving the fuse upwardly to the position shown in Figure 4, at which time the latching springs 19 carried by the door 8| will snap beneath the ears 80.

The door 8| is generally similar to the door 2 and is pivotally supported by a pintle pin 40 in the lower part of the housing. The door and housing jointly provide an opening through which the lower end of the fuse tube projects in much the same manner as in Figure 1. However, it should be noted the housing is preferably Cut away adjacent its lower portion and provided with side flanges 4| to provide space within which rocking portions of the lat-ching mechanism, to be hereinafter described, may move.

It is to be noted that the lower end of the fuse tube is provided with the lower collar or cupshaped member 82 having pins 83 projecting adjacent the outer portion rather than the inner portion of such cup-shaped member. These pins are engaged by the hooklike portions 84 of a restraining latch member. This restraining latch member is provided with arms 85 on opposite sides of the contact 12 to which it is pivoted, such arms being positioned above inwardly projecting arms 86 carried by the movable contact member 1| and beneath cam like portions 81 also carried by thc rocking contact member 1|. This rocking con tact member receives the lower end of the fuse link 88 which is clamped thereto by means of the thumb nut 89 and the spring contact arms 69 bear against the cam members 10 and tend to rock the pivoted contact member 1| in a clockwise direction, as indicated by the arrow ln Figure 4.

A compression spring 90 is interposed between the members 12 and 82 and urges the fuse tube downwardly. This downward motion of the fuse tube is normally resisted by the interlocking of the pins 83 with'the hooklike portions 84.

The operation of the apparatus is as follows: When the fuse blows, the member 'Il rocks in the direction indicated by the arrow under the infiuence of the members 69.' The cam-shaped portions 81 engage the upper faces of the arms 85 and rock the latches 84 out of engagement with the pins 83, thus releasing the fuse tube and allowing the fuse tube to be projected downwardly by means of the spring 90, and also assisted by the action of gravity.

It is to be noted that the construction oi the latching member is such that the force of the spring urging thc fuse tube downwardly is not transmitted to the fuse link and, consequently. does not strain the fuse link. This may be true of all forms of the invention, as illustrated, but is particularly true and particularly desirable -where a spring is employed to urge the fuse tube downwardly.

It will be seen that this invention provides a novel form of housed type expulsion fuse in which not only expulsion action is obtained, but also in which the fuse tube moves vertically downwardly from the housing and thus increases the gap in the electric circuit.

It will be seen further that the operation of the expulsion fuse will be extremely rapid as it has not only the expulsive action heretofore utilized in expulsion fuses, but also because whatever remains of the lower end of the fuse link after the blowing of the fuse is substantially instantly snapped out of the tube by means of the spring urged movable lower contact member.

It is to be noted, particularly with reference to Figures 1 and 3, that the latching means has an elongated sector-shaped portion 28 that holds the fuse tube in place during the period that the arc is being extinguished within the fuse tube and the link is being withdrawn from the fuse tube. This insures the retention of the upper contact of the fuse tube in engagement with the upper stationary contact during this interval.

Obviously the hook portion-s 84 of Figure 4 could be similarly elongated for the same purpose of prolonging the period after the initial rupturing of the fuse link before the fuse tube slides outwardly.

It will be seen furthery that the construction is simple, is easy to handle, that the fuses are easy to replace, .and that the device is eminently practical.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A fuse construction comprisingr a stationary supporting means having stationary contacts, a fuse tube slidably supported from said stationary means and having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being biased towards bodily sliding motion to separate at leastone of the spaced contacts of the fuse tube from the corresponding stationary contact, a fuse link Within said fuse -tube electrically joining said spaced contacts, and means controlled by said fuse link for restraining said fuse tube against sliding motion.

2. A fuse construction comprising a stationary support having stationary contacts, a fuse tube slidably supported and normally supported door for said housing, said housing having stationary contacts, a fuse tube slidably supported from said door and biased towards outward bodily motion from said housing, said fuse tube having spaced contacts normally engaging said stationary contacts, a fuse link electrically joining said spaced contacts, and mechanism controlled by said fuse link for holding said fuse tube against sliding motion. Y

4. A fuse construction comprising a housing, a door for said housing, said housing having stationary contacts, .a fuse tube slidably supported from said door and biased towards outward bodily motion from said housing, said fuse tube having spaced contacts normally engaging said stationary contacts, a fuse link electrically joining said spaced contacts, and mechanism controlled by said fuse link for holding said fuse tube against bodily sliding motion, said mechanism tending to pull said fuse link outwardly from said fuse tube.

5. A fuse construction comprising a housing, a door for said housing, said housing having stationary contacts, a fuse tube slidably supported from said door, said fuse tube having spaced contacts normally engaging said stationary contacts, a fuse link electrically joining said spaced contacts, mechanism controlled by said fuse link for holding said fuse tube against sliding motion, and means biasing said fuse tube towards outward bodily sliding motion from said housing.

6. A fuse construction comprising a housing, a door for said housing, said housing having stationary contacts, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being biased towards outward bodily sliding motion from said lh'ousing and being slidably supported within said housing, a fuse link electrically joining said spaced contacts, and mechanism interlocking with said fuse tube and restraining said fuse tube against outward bodily sliding motion, said mechanism being controlled by said fuse link, said door having a cut-out portion to permit the outward sliding of said fuse tube.

7. A fuse construction comprising a housing, a door ifor said housing, said housing having stationary contacts, a fuse tube having spaced contacts normally electrically connected to said sta-V tionary contacts, said fuse tube being biased towards outward bodily sliding motion from said housing and being slidably supported .by said door, a fuse link electrically joining said spaced contacts, and mechanism interlocking with said fuse tube and restraining said fuse `tube against outward bodily sliding motion,` said mechanism being controlled by said fuse link.

8. A fuse construction comprising a housing, a door for said housing, said housing having stationary contacts, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being biased .towards outward bodily sliding motion from said housing Vand being slidably supported by said l door, a fuse link electrically joining said spaced contacts, and mechanism interlocking with said fuse tube and restraining said fuse tube against outward bodily sliding motionY said mechanism being controlled by said fuse link, said door having a cut-out portion to permitl the outward bodily sliding of said fuse tube.

9. A quick action expulsion fuse comprising stationary supporting means having stationary contacts, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, means slidably supporting said fuse tube, latching means normally locking said fuse tube in operative position, spring means tending to release said latching means, and a fuse link mounted within said fuse tube and electrically connecting said spaced contacts, said fuse link being connected to a movable part of said latching means and normally restraining the releasing motion of said latching means, said latching means tending to withdraw said fuse link from said fuse tube.

10. A quick action expulsion fuse comprising stationary supporting means having stationary contacts, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, means slidably supporting said fuse tube, latching means normally locking said fuse tube in. operative position, spring means tending to release said latching means, a fuse link mounted within said fuse tube and electrically connecting said spaced contacts, said fuse link being connected to a movable part of said latching means and normally restraining the releasing motion of said latching means, said latching means tending to withdraw said fuse link from said fuse tube, and a spring urging said fuse tube outwardly with reference to said stationary supporting member.

11. In a fuse construction the combination of a stationary member having stationary contacts, a fuse tube having spaced contacts normally electrically engaging said stationary contacts, means slidably supporting said fuse tube with respect to said stationary member, said fuse tube being biased towards outward sliding motion from said stationary member, a. lever interlocking with means slidable with said fuse tube and normally restraining the outward sliding motion of said fuse tube, a second lever having cam means for rocking said rst mentioned lever towards releasing position and being spring urged towards releasing position, and a fuse link electrically joining said spaced contacts and restraining said second lever from rocking motion.

12. In a fuse construction the combination of a housing having stationary'contacts, a fuse tube having spaced contacts normally electrically engaging said stationary contacts and being slidably mounted within said housing. a spring urging said fuse tube outwardly from said housing, latching means for normally restraining the outward motion of said fuse tube, a second spring urging said latching means towards releasing position, the releasing motion of said latching means being independent of said rst mentioned spring, and a fuse link electrically connecting said spaced contacts and restraining said latching means against releasing motion.

13. A fuse construction comprising a, housing, a door pivoted adjacent its lower portion to said housing, said housing having stationary contacts, a fuse tube slidably carried by said door and biased towards outward sliding motion with respect to said door and said housing, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, latching means for normally restraining the outward motion of said fuse tube, and a fuse link electrically connecting said spaced contacts and restraining the releasing motion of said latching means, said housing having a cut-out portion t0 accommodate said latching means when said latching means rocks towards releasing position.

14. In a fuse construction a housing, a. door for said housing, stationary contacts carried by said housing, a fuse tube releasably interlocked with said door and slidably mounted upon said door, said fuse tube being biased towards outward sliding motion with respect to said housing and said door, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, latching means spring urged towards releasing position for normally holding said fuse tube against sliding motion, and a fuse link restraining said latching means and electrically joining said spaced contacts.

15. A fuse construction comprising a, housing, a door for said housing, said housing having stationary contacts, a fuse tube slidably supported from said door and biased towards outward motion from said housing, said fuse tube having spaced contacts normally engaging said stationary contacts, a fuse link electrically joining said spaced contacts, and mechanism including a lever biased towards releasing motion for hold ing said fuse tube against sliding motion, said mechanism being normally restrained from motion by said fuse link and having means delaying the release of said tube after the initial rupturing of said fuse link, whereby a sumcient period is allowed for the extinguishing of the arc within the fuse tube.

16. A fuse construction comprising a body portion having stationary contacts, a fuse tube slidably supported and'biased towards motion outwardly from said body portion, said fuse tube having spaced contacts normally engaging said stationary contacts, at least one of said spaced contacts moving away from the corresponding stationary contact when said fuse tube moves outwardly, a fuse link carried within said fuse tube and electrically joining said spaced contacts, a pivoted link having an elongated sector-shaped portion, and means carried by said fuse tube and normally engaged by said sector-shaped portion to restrain said tube against motion, said link being biased towards releasing motion and being restrained against motion by said fuse link, said elongated sector-shaped portion insuring the lapse of an interval of time after the initial rupturing of said link for the extinguishing of the are within the fuse .tube prior to the outward motion of said fuse tube.

17. In a fuse construction the combination of a stationary member having stationary contacts one of which includes a spring contact, a fuse tube, guiding means slidably supporting said fuse tube with reference to said stationary member, said fuse tube being biased towards outward sliding motion from said stationary member, means interlocking with said guiding means and normally restraining said fuse tube against outward sliding motion, said interlocking means including a lever, said fuse tube having a contact adjacent one end normally engaging one of said stationary contacts, and a fuse link electrically joining the contact of said fuse tube and said lever and normally restraining said lever from releasing motion, said lever being normally en gaged by said spring contact.

18. A fuse construction comprising a housing having stationary contacts and having a door, a fuse tube, guiding means carried by said door i'or holding and guiding said fuse tube, said fuse tube having spaced contacts normally electrically connected to said first mentioned contacts, a spring urging said fuse tube towards motion with reference to said door, said fuse tube having a fuse link electrically joining said spaced contacts, and means controlled by said fuse link normally restraining said fuse tube against motion with relation to said door.

19. A fuse construction comprising a housing having an open bottom and having contacts, guiding means mounted within said housing, a fuse tube slidably supported within said guiding means and biased for sliding motion towards said open bottom, said fuse tube having spaced contacts normally electrically connected to said first mentioned contacts, a fuse link electrically joining said spaced contacts, latching means to lock said tube in its operative position, said latching means including a lever to relieve the fuse link of excessive mechanical strain, said lever helping to withdraw the link when said fuse link blows.

20. A fuse construction comprising a housing having an open bottom and stationary contacts, a guiding means mounted within said housing, a fuse tube slidably supported within said guiding means and biased for sliding motion towards said open bottom, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, a fuse link electrically joining said spaced contacts, mechanism interacting between said tube and guiding meansfor restraining said fuse tube against sliding motion, said mechanism being controlled by said fuse link.

21. A drop-out fuse construction comprising a housing having an open front and bottom, a normally closed door for the front of said housing, a fuse tube slidably connected with said door and movable downwardly through said open bottom, said tube and door being pivotally supported from said housing, and means including a fuse link holding said fuse tube against slidingmovement relative to said door, said means being released upon overload, whereby said tube will move through the open bottom of said housing and the door will remain closed.

22. A fuse construction comprising a housing having stationary contacts and having a door, a fuse tube, guiding meanscarried by said door for holding and guiding said fuse tube, said fuse tube being detachable from said door and being movable with respect to said door, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being biased towards motion with respect to said door, said fuse tube having a fuse link electrically joining said spaced contacts, means controlled by said fuse link normally restraining said fuse tube against motion with relation to saiddoor, and means for holding said door closed after said fuse tube has been removed from said door.

23. A fuse construction comprising a housing having stationary contacts and having a door, a fuse tube, guiding means detachably carried by said door for supporting and guiding said fuse tube, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being biased towards motion with respect to said door, said fuse tube having a fuse link electrically' joining said spaced l0 contacts, means controlled by said fuse link normally restraining said fuse tube with relation to said door, and means for holding said door closed after said fuse tube has been removed from said door.

24. A fuse construction comprising a housing having an open bottom and stationary contacts, a guiding means mounted within said housing, a fuse tube slidably supported within said guiding means and biased for sliding motion towards said open bottom, said fuse tube having spaced contacts normally electrically connected to said stationary contacts, and a fuse link connecting said spaced contacts and restraining said fuse tube against sliding motion.

25. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means detachably interlocking with said door, a fuse tube lhaving spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, and a fuse link electrically connecting said spaced contacts and restraining said fuse tube against sliding motion.

26. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means detachably interlocking with said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, means biasing said fuse tube towards downward sliding motion, and a fuse link electrically connecting said spaced contacts and restraining said fuse tube against sliding motion.

27. A drop-out fuse construction comprising a housinghaving an open front and bottom and having stationary contacts, a door for said house ing, guiding mea-ns detachably interlocking with said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, restraining means carried by said guiding means for temporarily locking said fuse tube against sliding motion, and a fuse link electrically connecting said spaced contacts and holding said restraining means against releasing movement.

28. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding meansdetachably interlockingwith said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, restraining means carried by said guiding means for temporarily locking said fuse tube against sliding motion, said restraining means being biased towards releasing movement, and a fuse link electrically connecting said spaced contacts and holding said restraining means against releasing movement.

29. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means detachably interlocking with said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, means biasing said fuse tube towards downward sliding motion, restraining means carried by said guiding means for temporarily locking saidfuse tube against 11 sliding motion, and a i'use link electrically connecting said spaced contacts and holding said restraining means against releasing movement.

30. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means detachably interlocking with said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being slidably carried by said guiding means, means biasing said fuse tube towards downward sliding motion, restraining means carried by said guiding means for temporarily locking said fuse tube against sliding motion, said restraining means being biased towards releasing movement, and a fuse link electrically connecting said spaced contacts and holding said restraining means against releasing movement.

31. A drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means supported from said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being carried by said guiding means and being movable from operative to inoperative position, a fuse link electrically connecting said spaced contacts and restraining said fuse tube against movement, said fuse tube being bodily removable from said door, and means for holding said door closed after said fuse tube has been removed from said door.

32. A. drop-out fuse construction comprising a housing having an open front and bottom and having stationary contacts, a door for said housing, guiding means detachably interlocking with said door, a fuse tube having spaced contacts normally electrically connected to said stationary contacts, said fuse tube being movably carried by said guiding means and being movable from operative to inoperative position, means cooperating with said guiding means and said fuse tube for biasing said fuse tube towards inoperative position, a fuse link electrically connecting said spaced contacts and restraining said fuse tube against motion, said guiding means and said fuse tube being bodily removable from said door, and means for holding said door closed after said guiding means has been removed.

33. An automatic current interrupting switch comprising a housing having contacts and having an opening through its bottom, a door for said housing, guiding means carried by said door, an arcing tube slidably carried by said guiding means and biased towards the opening in the bottom of said housing, an expulsible conductor within said tube normally electrically joining said contacts, a relatively stationary member, and latch mechanism controlled by said conductor and carried by said relatively stationary member for normally restraining said tube against sliding motion, said conductor being released on the occurrence of an overload in an electric circuit.

34. A housed type drop-out switch comprising an insulating housing having an opening in its bottom and having spaced terminals therein, an arcing tube including contacts engageable with said terminals, and a conductor connecting the contacts, relatively stationary guiding means for said arcing tube, said arcing tube being slidably carried within said guiding means, and latch mechanism controlled by said conductor for normally restraining said tube against sliding mo- 12 tion, said conductor being released on the occurrence of an overload in an electric circuit.

35. A circuit interrupting switch structure having stationary contacts and an arcingtube open at its lower end and having spaced contacts, an

expulsible conductor in said tube connecting said spaced contacts and releasably held therein, casing means enclosing said switch structure, guiding means slidably holding said tube with the spaced contacts in engagement with said stationary contacts, latching means normally holding said tube against sliding motion, and means operable on overload in an electric circuit to cause release of said latching means.

36. A drop-out circuit interrupting switch structure comprising a housing having an open front and bottom, a normally closed door for the front of said housing, an arcing tube open at its lower end and slidably connected with said door and movable downwardly through said open bottom, said tube and door -being pivotally supported from said housing, an expulsible conductor in said tube releasably held therein, latching means normally holding said tube against sliding movement, and means actuated on the occurrence of an overload in an electric circuit to release said latching means.

37. A circuit interrupting switch structure comprising a housing having stationary contacts and having a door, guiding means carried by said door, an arcing tube guided by said guiding means, a spring urging said tube to move relative to said door, said tube having spaced contacts normally electrically connected to said first mentioned contacts, said tube having an expulsible conductor therein connecting said spaced contacts, latching means normally holding said tube against motion, and current controlled means for releasing said latching means upon the occurrence of an overload in an electric circuit.

38. A circuit interrupting switch comprising a pair of stationary contacts, guiding means, an arcing tube slidably supported within said guiding means and biased for sliding motion, said tube having spaced contacts normally electrically connected to said stationary contacts, an expulsible conductor in said tube electrically joining said spaced contacts, mechanism interacting between said tube and guiding means for re. straining said tube against sliding motion, and current controlled means releasably controlling said mechanism.

39. In an automatic circuit interrupting switch, an insulating housing having an open bottom and terminal contacts therein, a movable arcing tube with an expulsible conductor therein, movable latch means to engage and hold the tube in circuit closing position, and means to release the tube from the latch for the bodily movement of the tube through the open bottom.

40. In an automatic circuit interrupting switch, an insulating housing having an open bottom and terminal contacts therein, an arcing tube movable between closed circuit and open circuit positions, an expulsible conductor in said tube, means to latch the tube in closed circuit position by an approximately lateral motion of the tube, and means to release the tube from closed circuit position for the bodily movement of the tube through said open bottom.

41. A drop-out current interrupting device comprising a housing having an open lower end and having spaced terminals therein, an arcing tube having spaced contacts normally electrically connected to said terminals and slidably supported-in said housing for bodily movement relative to said terminals, thereby to withdraw at least oneA of its contacts from electrical connection with one of said terminals, said open lower end of said housing permitting free sliding movement of saidlaitube, releasable latching mechanism normally holding said tube against sliding movement, and latch releasing means responsive on the occurrence of an overload in an electric circuit including said spaced terminals for releasing said latching mechanism, said means including a conducting element in said tube, whereby said tube will be freely slidable when said latching mechanism is released.

42. A drop-out current interrupting device comprising an insulating supporting structure having spaced terminals, an arcing tube having spaced contacts normally electrically connected to said terminals and slidably supported by said structure for bodily slidable movement relative to said terminals, thereby to withdraw at least one of its contacts from electrical connection with one of said terminals, releasable latching mechanism normally interacting between said supporting structure and tube to hold said tube against sliding movement, and latch releasing means responsive on the occurrence oi' an overload inan electric circuit including said spaced terminals for releasing said latching mechanism, said means including a conducting element in said tube, whereby said tube will be freely slidalble when said latching mechanism is released.

43. In a fuse of the class described, a fuse tube.

a fuse link in the tube provided with a terminal lead, a sleeve movable with respect to the tube, a springwflonproducing relative movement of the e when the link is melted, and an arm pivote,V` I o the sleeve and attached to the terminal lead y,for retracting the terminal lead at an accelerated rate when the link melts.

44. In a circuit breaker, spaced contact terminals, means for mounting a'fuse housing connected between said terminals including a fuse housing supporting element arranged to provide for longitudinal sliding of the fuse housing relative to said supporting element, means arranged to exert force on the fuse housing tending to effeet longitudinal sliding ofthe fuse housing relative to said element and latching means for holdinf.r the fuse housing against such longitudinal sliding. said latching means being arranged to be released by operation of a fuse in the fuse housing thereby to permit said force exerting means to effect longitudinal sliding of the fuse housing.

45. In a circuit breaker, upper and lower terminals, means for mounting a fuse housing connected between said terminals including a supporting collar for the lower end of the fuse housing arranged to provide for longitudinal sliding of the fuse housing in the collar, a movable contact member for engagement with the upper end of said 'fuse housing, a spring interacting between said contact member and said upper terminal to exert force on the fuse housing tending to effect longitudinal sliding ofthe fuse housing in said collar, and latching means at the lower end of said fuse housing for holding it against such longitudinal sliding, said latching means being arranged to be released by operation of a fuse in the fuse housing thereby to permit said contact member and said spring to eoct longitudinal sliding of the fuse housing,

14 46. In a circuit interrupter, in combination, a iirst and a second stationary terminal, a fuse tube having fuse terminals and a fuse link therein electrically interconnecting them, one of said fuse terminals being in contact engagement with said first stationary terminal, the other of said fuse terminals comprising a metallic sleeve through which said fuse tube is relatively movable and being electrically connected to said second stationary terminal, and meansv for producing relative movement between said fuse tube and said sleeve in response to blowing of said fuse link to disengage said one fuse terminal from said first stationary terminal.

47. In a circuit interrupter, in combination, a first and a second stationary terminal, a fuse tube having fuse terminals and a fuse link therein electrically interconnecting them, one of said fuse terminals being in contact engagement with said iirst stationary terminal, the other of said fuse terminals comprising a metallic sleeve through which said fuse tube is relatively movable and being electrically connected to said second stationary terminal, biasing means for producing relative movement between said fuse tube and said sleeve, and a lever pivotally mounted on said sleeve and restrained from movement by connection of said fuse link thereto at a point remote from its axis of rotation for preventing said relative movement until said fuse link blows.

48. A fuse construction comprising a housing having a iirst and a second stationary contact and having a door, a fuse tube having a closed end and an open end and having a first con-v tact adjacent the closed end thereof, and a second contact spaced from said first contact, said first and second contacts of said fuse tube normally engaging said first and second stationary contacts respectively, means for slidably guiding said fuse tube, said fuse tube being biased towards sliding motion with respect to said guiding means, said fuse tube having a fuse link electrically joining the said rst and second contacts of said fuse tube, means controlled by said fuse link normally restraining said fuse tube against sliding motion with respect to said guiding means and releasing said fuse tube upon rupture of said fuse link, said first contact of said fuse tube adjacent the closed end thereof moving away from said first stationary contact upon rupture of the fuse link, and means for holding lsaid door closed after said fuse tube has moved with respeci: to said guiding means.

WILLIAM O. SCHULTZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNI'I'ED STATES PATENTS 

